Wave-modifier for x-ray systems.



G. M. PEABODY. WAVE MODIFIBR FOR X-RAY SYSTEMS.

APPLICATION FILED OCT. 2, 1913.

Patented Feb. 23, 1915.

4 UNITED snares PATENT OFFICE.

CHARLES M. PEABODY, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR TO THE KNY- SCHEERER COMPANY, A CORPORATION OF NEW YORK.

wAVE-MODIFIER FOR X-RAY SYSTEMS.

To all whom it may concern Be it known that I, CHARLES M. PEABODY, a citizen of the United States, and a resident of South Orange, New Jersey, (whose 0stoiiice address is care of Kny-Scheerer omany, No. 404 West Twenty-seventh street,

'm the borough of Manhattan, county, city,

an alternating current into a pulsating cur rent.

In machines of the type mentioned, according to the relative circumferential extent of the commutating parts, a definite extent of each of the various electromotive force or current waves is made available in the working circuit. It is usual to employ the crest portion of these Waves symmetrical on opposite sides of the apex of the wave crest. Present day activities in X ray work have become such that wave portions of a predetermined extent relative to the entire wave as well as of a predetermined angular position in the wave cycle are best adapted to some particular use. For instance, some X-ray tubes may work at the highest efficiency when excited by a wave Portion com prising a very considerable extent of the wave above the zero line whereas other tubes cannot be operated with any degree of chiciency unless the excitation is limited to the v apices of the wave crests.

The object of the present invention is to provide for the modifying of the wave portions employed in an X-ray system so that, by selective variation, those 1 portions desired for the work in hand may be made available, and so that the undesired wave portions may be discarded.

With this end in view there is contemplated within the invention the employment of at least a pair of cooperating commutating parts, which, of course, may be multi- Specification of Letters Patent.

Application filed October 2, 1913. Serial No. 792,935.

of the parts revolves about a fixed axis, and the other of the parts is relatively fixed against revolution, both normally lying substantially in the normal plane of revolution of the revolving part; and means for varying the circumferential extent of said conducting are which portion cobperates With said conducting finger to cause a flow of current from one to the other, all for the pur pose of selectively varying the number of degrees or the angle of rotation through which the said two parts cooperate to complete the working circuit.

Especially on account of the high potentials employed in X-ray work considerable difficulty is experienced even in commutating an alternating current into a pulsating current. To provide in such a commutator means for selectively varying the extent of the current wave made serviceable presents a serious engineering problem. The space available for any purpose in a commutating machine is not only mechanically limited, but much of that space mechanically permissible is unavailable on account of the high electric potentials present. It has been found that the best results are obtainable by employing conducting arcs which are relativelyfixed against revolution, but at least a portion of which is rotatable out of the plane of revolution of the conducting finger. By making the conducting arc in sections with only a central section rotatable upon a radial pivot, a wide range of selective adjustment may be effected without causing impermissible cross discharges to the movable section of the-contacting arc. In connection with such an arrangement the rotatable central section of the conducting arc may be adjusted into its various positions merely by attaching a cord of insulating material to one of its ends.

The above will be pointed out more particularly in the following claims wvhich should be read in connection with the following specifica-tion which is descriptive of an illustrated embodiment of the invention shown in the accompanying drawings, in which like characters designate corresponding parts, which form a part of this application, and in which Figure 1 is a perspective view of a rectifier embodying this-invention; Fig. 2 is a detailed view of the means for modifying the extent of available wave portion; Fig.

I In Fig. 1 is illustrated an apparatus fundamentally similar tothat shown diagrammatically in Fig. 6 of the patent to Blum, eference to which has been made.

1 is a containing cabinet for conveniently housing and mounting the various parts; 2 is a suitable switchboard forthe electric control; 3 is a source of alternating current and of mechanical power. for the revolving commutating partsC. This source 1 3 is illustrated as a synchronous generator.

The revolving parts C aredriven through the medium of theshaft '4 coupled to the source ofpower 3 through the medium of a suitable coupling 5. T indicates any suitable form of high potential power trans-- former and is supplied with alternating current from the source of power 3 through the leads 6 and 7 feeding the primary winding of the transformer T. The secondary terminals of the transformer are indicated-by 8 and 9. V

Fixed to the shaft 4 are a plurality of diametrically parallel spider arms 10 and 11. Angularly positioned at 90 relatively to the arms. 10 and 11 are a plurality of diametrically parallel spider arms 12 and 13 which are likewise fixed to the shaft 4.

- The arms 11 and. 12 occupy substantially thesame plane at right angles to the shaft 4. Fixed to the ends of these arms are conducting fingers 14,45, 16, 17, 18, 19, 20, and 21, mounted to revolve in circular paths about the fixed axis of the shaft 4. These conducting fingers are electrically connected in pairs, 14 and 15 by the rod 22'; 16 and I? by the rod 23; 18 audit? by the rod 24; and 20 and 21 by the rod 25,.

Cooperating conductively for the working circuit with the revolving conducting fingers 14, et cetera, are the conducting arcs 26, 27, 28, 29, 30, and 31 relatively fixed against revolution.

For the purposes of this application each conducting finger 14, et cetera, and one of the conducting arcs such as 26 lying in the plane of revolution of the finger are together termed a pair of cooperating commutating parts, one of which, in the embodiment illustrated, a conducting finger such as 14, being adapted to revolve about the fixed axis of the shaft 4 and theother, in the illustrative embodiment the'arc 26,

being relatively fixed against revolution and lying in the normal plane of revolution of the other part 14. It is of course to'be understood that this language likewise inclusively describes a structure in which the conducting fingers 14 et cetera are the relatively fixed parts and the conducting arcs 26 et cetera are the revolving parts attached to the ends of the spider arms 10, 11, 12,

- and 13. In either case the conducting arc should be normally concentric with the path of revolution of the revolving part, the common center being the axis of the shaft 4.

In the embodiment illustrated the secondary terminals 8 and 9 of the transformer T are connected to-theconducting arcs 29 and 28 respectively by the leads 40 and 41. It is therefore obvious that the connections of the revolving and rotating commutatingparts C are such that the conducting arcs 26 and 27 will constitute the terminals for one working circuit and the conducting arcs 30, and 31 terminals for'another and separate workingcircuit. It is of course understood that suitable leads and binding posts .if desired are to be provided to connect with these arcs 26, 27, 30 and 31. Furthermore, it is to be understood that this invention is by no means limited to the precise number of commutating parts illustrated and described because any multiplication thereof may be effected to accomplish any of thewell known ends in the art, as for instance, those described in'the patent to Blum previously referred to.' r

The present invention has to do withthe means for varying the extent of the'angl'e" of rotation throughout which the cooperaing commutating parts actually cotiperate f to close a secondary circuit. This means isillustrated in detall in Figs. 2 and 3 for the conducting arc 28. The conducting are 28 is preferably formed out of a suitablecurved strip of metal which is severed short 'of its ends by the diagonal cuts 42 and 43 into three sections 44, 45, and 46. The end sections'44 and 46 arefixed to suitable insulating members such as 47 and 48. The

main central section 45 is pivoted as by the bolt or rivet 4.9m the insulating support 47 and is shown-fitted with a spiral spring 50 located about the bolt 49 and tending to rotate the central section 45 in a counter-clock-wise direction when viewed in the position of Fig. 3. The inclined cuts 42 and 43 cause the end pieces 44 and 46 to serve as stops to limit this counter-' clock-wise rotation of the center part 45 so that when the three parts 44, 45, and 46 are in normal position the central part presses firmly against the end parts to complete the entire conducting are 28, or where the end parts are omittedhthe cord 53 mav serve as a stop. One end of the central part 45 has suitable means such as the wvall of the perforation 52 for attaching a flexible non-conducting cord 53. This cord 53 passes diagonally upward and to the right over a suitable guide 54 thence along the top Wall of the cabinet through the exit bushing 54 to an adjusting means 55. In like manner a cord 56 is attached to a similar central portion for the conducting are 29 which is of symmetrical construction to the are 28. This cord 56 passes over its guide 57, likewise through the bushing 54, and to its attachment with the adjusting member 55. A series of scaled sockets 58 for the reception of the plug 55.

the terminals 26 and 27 or the terminals 30 and 31 and would be m of Fig. 4. Immediately upon the rotation of the central portions 45 into the position shown in dotted lines in Fig. 3, the wave portion delivered by the said terminals would become limited as shown for example by the wave portion Y. The more the central portion 45 is tilted toward right angles to its normal position the less is the circumferential extent thereof cotiperative in the plane of revolution for the other commutating part. When exact right angular position is reached practically only the apex ofthe wave crest is available in the working circuit as may be illustrated by the wave portion Z in Fig. 4.

In the preferred form the adjustable conducting arcs may be limited to the conducting arcs directly connected with the terminals of the secondary transformer T although it is of course to be understood that these adjustable conducting arcs might take the position of the arcs 30 and 31 and the arcs 26 and 27 Without changing the spirit of the invention.

What is claimed and What is desired to be secured by United States Letters Patent is:

1. A commutator, for X-ray systems comprising a pair of cooperating commutating parts, one being adapted to revolve about a fixed axis and the other being relatively fixed against revolution substantially in the normal plane of revolution of the other part, one of said parts being a conducting finger and the other of said parts being a conducting are normally concentric with said fixed axis; and means for varying the circumferential extent of said conducting arc which cooperates with said conducting finger for the purpose of selectively modifying the commutated wave, said means comprising a radial pivot about which at least a portion of said are may be swung out of said normal plane of revolution.

2. A commutator, for X-ray systems comprising a pair of cooperating commutating parts, one being adapted to revolve about a xed axis and the other being relatively fixed against revolution substantially in the normal plane of revolution of the other part, one of said parts being a conducting finger and the other of said parts being a conducting arc normally concentric with said fixed axis; and means for varying the circumferential extent of said conducting are which coiiperates with said conducting finger for the purpose of selectively modifying the commutated wave, said means comprising a radial pivot about which at least a portion of said are may be swung out of said normal plane of revolution, a spring yieldingly holding said portion in normal position and a member attached to said are for adjusting its position.

3. A commutator for X-ray systems comprising a conducting finger adapted to revolve about a fixed axis; and a conducting are normally concentric with said axis and cooperating with said conducting finger and fixed against revolution, said conducting arc comprising a plurality of sections one of which is radially pivoted to rotate out of its normal plane to vary the extent of said conducting are cooperating with said conducting finger.

4. In a commutator for X-ray systems, a conducting are comprising fixed end sections and a radially pivoted central section, the meeting ends of said sections normally mating closely together but ermitting the rotation of said central section out of its normal plane.

5. In a commutator for X-ray systems, a conducting arc comprising fixed end sections and a radially pivoted central section, the meeting ends of said sections normally mating closely together and mutually forming stops to prevent the rotation of said central section in one direction but permitting its rotation in the opposite direction out of its normal plane.

6. In a commutator for X-ray systems, a conducting arc comprising fixed end sections and a radially pivoted central section, the meeting ends of said sections normally mating closely together and mutually forming stops to prevent the rotation of said central section in one direction but permitting its rotation in the opposite direction out of its normal plane; and spring means tending to hold said central section in normal position.

7. In a commutator for X-ray systems a conducting sr'c at least a portion of which In Witness whereof, I have signed my is radially prvoted; a spring means tending name to this specification, in the presence of to rotate said portion 1n one direction; two subscribing Witnesses.

means for positively rotating said portion CHARLES M. PEABODY. in the opposite direction; and a scale for Witnesses:

marking the position of said portion rela- SIDNEY NEwBoRo,

tively to a normal angular position. LESTER L. CALLosE.

copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. G. 

